Matthew says only "a woman" (26:7). Who was she?

Matthew doesn't say. "Now when Jesus was in Bethany, in the house of Simon the leper" (26:6), "a woman came to him having an alabaster jar of very expensive ointment, and she poured it on his head as he sat at the table" (26:7). Jesus says, "what this woman has done will also be spoken of as a memorial of her" (26:13): what she did is to be told, and Matthew doesn't give her name. Mark's telling also says "a woman came" (Mark 14:3). John's Gospel tells of an anointing at Bethany too (John 12:1-8), and Favor's John 12 sets the tellings of Mark, Matthew and John side by side in its question on whether they are the same anointing, and doesn't say whether they tell one event or two. These notes don't name the woman Matthew leaves unnamed, and don't say either.